For correct diagnosis of various diseases, e.g. cancer, biopsies are often taken. This can either be performed via a lumen of an endoscope or via needle biopsies. In order to find the correct position where the biopsy has to be taken, various imaging modalities are used such as X-ray, Magnetic Resonance Imaging (MRI) and ultrasound. For example in most of the cases of prostate cancer the biopsy is guided by ultrasound. Although helpful, these methods of guidance are far from optimal. The resolution is limited and, furthermore, these imaging modalities can in most cases not discriminate between benign and malignant tissue.
In order to relay visible images of the tissue to be scanned at the tip of the endoscope, biopsy needle or other miniaturized inspection devices, several systems have been employed: i) relay lens system, e.g. as in rigid endoscopes, ii) fiber bundle, e.g. in flexible endoscope, iii) camera sensor at the tip of the scanning device, e.g. in videoscopes or iv) fiber scanner located in front of a fixed lens system, e.g. in endomicroscopy.
Most of these systems, e.g. relay lens system and fiber bundles, involve complicated optics making these systems expensive and hence not suitable for production of disposable components. Also camera sensor in videoscope has the disadvantage that the image sensor must have a small lateral view, which makes these image sensors complicated and expensive as more common, and cheap technology, as in mobile phone cameras, cannot be applied. Finally, fiber scanners located in front of a fixed lens system have the disadvantage that in order to a have a reasonable field of view (FOV) a complicated lens system is required in combination with a rather large stroke of the fiber end as described for example in US2005/0052753.
Thus far, none of the above approaches seems to be a viable road towards an affordable disposable endoscope with a reasonable field of view.
In summary, previously disclosed fiber-scanning systems with a reasonable field of view (FOV) applies complex and expensive lens systems making them expensive and disadvantageous for use in disposable optical probes.